Deciphering the roles of RIFIN and STEVOR parasite antigens in severe malaria pathogenesis via transcriptomics and immune profiling

项目摘要 尽管经过了几十年的研究，恶性疟原虫疟疾仍在夺走数十万儿童的生命。 在撒哈拉以南的非洲地区。对严重疟疾的脆弱性是复杂的，涉及宿主和寄生虫 因素A型血是严重疟疾的既定危险因素，而O型血与 防止出现复杂症状。这种现象的确切机制还不完全清楚 但可能涉及由特定寄生虫抗原介导的相互作用。RIFIN和STEVOR是高度多样化的 寄生虫蛋白家族，显示在受感染的红细胞表面。最近的实验室研究 表明这些抗原可能通过多种机制加剧疟疾的严重性，包括粘附， 到附近的红细胞，形成“寄生虫”，包裹寄生虫，并保护它免受免疫清除。 某些RIFIN优先结合A型红细胞。STEVOR具有类似的约束偏好， 血型糖蛋白C，另一种红细胞表面蛋白。这些有趣的发现表明，RIFIN和 STEVORs可能是恶性疟原虫毒力的核心，并导致对严重疾病易感性的差异 血型之间的区别尽管在体外与严重的疟疾脆弱性之间存在着有希望的联系， 到目前为止，RIFIN和STEVOR家族的多样性阻碍了对这些家族的全面研究。 临床感染中的抗原。该提案的目标是确定RIFIN和STEVOR亚型， 与非洲儿童的严重疟疾有关。我们将从患有以下疾病的儿童中获取血液和血清样本： 马里、马拉维和乌干达的严重或非严重疟疾，代表撒哈拉以南非洲的三个地区 疟疾传播模式不同在目标1中，我们将鉴定在大肠杆菌中表达的rif和stevor转录本。 使用无参考RNA-Seq的个体血液样品，然后比较转录物亚组的丰度 严重和非严重疟疾之间的区别。在目标2中，我们将分析针对全面的 RIFIN和STEVOR变异体的微阵列，以确定严重疟疾儿童的免疫“缺口”， 到非严重疟疾。RIFIN和STEVOR抗原亚型优先表达和/或不优先表达 在严重疟疾感染中血清识别的可能是发病机制的重要介质。RIFIN认为， 在严重的病例中，A型血占主导地位可能是这一群体脆弱性的关键方面。拟议 目的将有助于阐明RIFIN和STEVORs在严重疟疾发病机制中的作用，并为研究提供信息。 开发量身定制的疫苗和疗法，以保护撒哈拉以南非洲最危险的儿童。的 申请人将开发和应用转录组学，免疫流行病学和国际实践技能 临床研究设计和管理，这对他作为21世纪世纪分子生物学家的职业生涯至关重要。 流行病学家

PROJECT SUMMARY Despite decades of research, Plasmodium falciparum malaria continues to kill hundreds of thousands of children in sub-Saharan Africa each year. Vulnerability to severe malaria is complex, involving both host and parasite factors. Blood type A is an established risk factor for severe malaria, whereas blood type O is associated with protection from complicated symptoms. The exact mechanism of this phenomenon is incompletely understood but may involve interactions mediated by particular parasite antigens. RIFINs and STEVORs are highly diverse parasite protein families that are displayed on the surface of infected red blood cells. Recent laboratory studies suggest that these antigens may exacerbate malaria severity through multiple mechanisms, including adherence to nearby red blood cells to form “rosettes” that envelop the parasite and protect it from immune clearance. Certain RIFINs bind preferentially to type A red blood cells. STEVORs have a similar binding preference for glycophorin C, another red blood cell surface protein. These intriguing findings suggest that RIFINs and STEVORs may be central to P. falciparum virulence and drive differences in susceptibility to severe disease between blood types. Despite promising in vitro links to severe malaria vulnerability, the immense diversity of the RIFIN and STEVOR families has so far precluded the comprehensive study of these antigens in clinical infections. The goal of this proposal is to identify RIFIN and STEVOR subtypes that are associated with severe malaria in African children. We will obtain blood and serum samples from children with severe or non-severe malaria in Mali, Malawi, and Uganda, representing three regions of sub-Saharan Africa with distinct malaria transmission patterns. In Aim 1, we will identify the expressed rif and stevor transcripts in individual blood samples using reference-free RNA-Seq, then compare the abundance of transcript subgroups between severe and non-severe malaria. In Aim 2, we will profile antibody responses against a comprehensive microarray of RIFIN and STEVOR variants to identify immune “gaps” in children with severe malaria compared to non-severe malaria. RIFIN and STEVOR antigen subtypes that were preferentially expressed and/or not serorecognized in severe malaria infections may be important mediators of pathogenesis. RIFINs that predominate in severe cases with blood type A may be critical aspects of this group’s vulnerability. The proposed aims will help clarify the role of RIFINs and STEVORs in severe malaria pathogenesis and inform the development of tailored vaccines and therapeutics to protect the most at-risk children in sub-Saharan Africa. The applicant will develop and apply hands-on skills in transcriptomics, immunoepidemiology, and international clinical research design and management, critical to his intended career as a 21st century molecular epidemiologist.